/Engine/Plugins/Runtime/RigVM/Source/RigVM/Public/RigVMFunctions/Math/RigVMMathLibrary.h
See - "Computing Euler angles from a rotation matrix" by Gregory G. Slabaugh Each spatial orientation can be mapped to two equivalent euler angles within range (-180, 180)
static FVector GetEquivalentEulerAngle ( const FVector & InEulerAngle, const EEulerRotationOrder & InOrder )